I know that it has to be an illusion, but my iPhone screen seems to be shrinking. I noticed a definite reduction in iPhone screen real estate about a week after getting my iPad. At first, I thought that I was making a subconscious comparison between the two devices when I have both in front of me, which seems reasonable since, side by side, the iPad can swallow the iPhone whole and still have room for dessert.

The problem with that theory is that the iPhone’s screen looks dinkier now even when the iPad is not around. 

I’m a pinball fan and use to enjoy playing The Deep and Wild West Pinball on my iPhone a lot. Since I started playing them on the iPad (they’ve been combined and upgraded into one app simply called Pinball HD), the iPhone version feels as if it were designed for nearsighted Hobbits.

It’s not just the games. Composing any sort of document has always been a bit of a challenge on the iPhone. True that the iPhone, with its virtual keyboard, made text input on phones far less a chore than it was on pre-iPhone devices, but I can actually write whole articles on the iPad’s virtual keyboard and not hate the experience. And I don’t feel as if I need a magnifier to see what I’m typing. (This article was written on the iPad in Notes, the notepad app Apple includes with the iPad. This would have been too painful to do in any app on the iPhone.)

I was concerned about the weather other day, what was a blue sky speckled with small cottony clouds had become hazier with darker and far more menacing nimbus gathering in the distance. As per habit I whipped out my iPhone and fired up The Weather Channel app to check the radar. The app produced an image as it always has, but this time I noticed I was squinting to see where the rain was falling. I never had to squint at my iPhone before.

On the iPad, The Weather Channel app has maps that are huge and I can easily see which way the rain was heading. While the iPhone version offers motion radar, the iPad version does it in more intervals and at higher resolution.

It’s not just because the iPad has a bigger screen. I don’t get the perception that my iPhone has shrunk after using my 21-inch iMac. In fact, up until recently, my iPhone felt more like an extension of my iMac, a mobile window into my digital life. My iPad, on the other hand, has supplanted my iMac in many functions. I mentioned that I’ve written some articles on my iPad, I also prefer to read my email and bounce around the Web on it, even when I’m home. The reason is that I don’t have to go to the iPad as I have to with my iMac, the iPad comes with me. While my iPhone is more portable, it now feels less like a window and more like a peephole.

And it’s getting worse. I’m starting to carrying the iPad with me more, even though I have yet to activate the 3G portion. When I’m near a WiFi hotspot and I feel my iPhone alerting me to a newly arrive email I’ll stop what I’m doing and pop open the iPad because I much prefer reading email on it than on my iPhone. (I can hardly wait for iPhone OS 4 to hit the streets with its multitasking and other iPad-enhancing features.) 

I realize my iPhone screen is made of glass and not wool, but I could swear that if I took a measurement I’d find that my phone’s screen is 20 percent smaller today than it was when I first bought it two years ago. I’m hoping Apple’s new iPhone will give me back some of those lost square centimeters.

In the meantime, I’ll have to continue squinting at my iPhone. I suppose I’ll eventually breakdown and pay AT&T for iPad 3G service, which reeks to high Heaven, if you want my opinion. (I’m not saying the iPad access to 3G should be free, I’m saying iPhone users, who already pay a premium just because of the phone they use, shouldn’t be double billed for using the same service.) When I do, I have a feeling my iPhone’s screen will be come downright Lilliputian.